[llvm] [NFC] Remove UnwindTable dependency on CIE, and FDE (PR #142520)

[Igor Kudrin via llvm-commits]

https://github.com/igorkudrin commented:

I'm not sure that I understand the purpose of this patch. The stated goal is to eliminate the dependency on CIE and FDE, but the `UnwindTable` class didn't use them anyway. Only its static constructors were aware of them. The patch transforms these static constructors into free functions, so a public method is now required to initialize the created object. The old code created an immutable object, which is usually preferable from a design perspective.

https://github.com/llvm/llvm-project/pull/142520